Copying machine for documents using a heat-and-light process

ABSTRACT

Apparatus for making copies of documents by the light-and-heat process including an exposure station and a heat development station in integral relation. The exposure station consists of a light box with reflective walls that slope inwardly from a transparent pressure plate or exposure station to a perforate top. Housed within the sloping walls are an arcuate reflector and light sources for exposure of a document and a light-sensitive intermediate. The heat development station consists of an openfaced shoe, a rotatable roller having a compressible surface and a stripper for separating the intermediate and the developed copy sheet and for imparting to the copy sheet a reverse curl.

United States Patent inventors John V. Rule; 7 [56] References Cited Marvin A. Stoll, both of St. Paul, Minn. UNITED STATES PATENTS Q A- 970 2,799,773 7/1957 Schwartz 240/47 P d 281971 3,221,631 12/1965 Bernstein 355/113 9" Mm MM ha 3,288,047 11/1966 Limberger 355/100 commmy 3,467,470 9/1969 Donnelly etal 355/115 St. Paul, Minn. Primary Examiner-Samuel S. Matthews Assistant ExaminerD. J. Clement Attorney-Kinney, Alexander, Sell, Steldt & Delahunt Continuation of application Ser. No. 729,218, May 15, 1968, now abandoned. This application Jan. 16, 1970, Ser. No.

3 545 ABSTRACT: Apparatus for making copies of documents by the light-and-heat process including an exposure station and a COPYING MACHINE FOR DOCUMENTS USING A heat development station in integral relation. The exposure "EA'LANILLIGHT PROCESS station consists of a light box with reflective walls that slope 3 chi 3 Buying Fi inwardly from a transparent pressure plate or exposure station to a perforate top. Housed within the sloping walls are an arm 355 113 cuate reflector and light sources for exposure of a document n v G63) 21/14 and a light-sensitive intermediate. The heat development stah 355 l 00 tion consists of an open-faced shoe, a rotatable roller having a Field of Sean: 5 210 4 compressible surface and a pp for separafing he inter 1 1 l 7 mediate and the developed copy sheet and for imparting to the copy sheet a reverse curl.

l I o .di o I 3/ 3/ A; 26 \\'1' 1 a I I l \i i l r z y 3 I 1 1 i l /3 I l 11 1 a A l i 2/ i9 i 0'- 2 v I '4 1 1// r'/ //x// /I l w I COPYING MACHINE FOR DOCUMENTS USING AHEAT- AND-LIGHT PROCESS This application is a continuation of copending application Ser. No. 729,218 now abandoned filed May 15, 1968.

This invention relates to the copying of documents and other graphic originals by a process involving light exposure and heat development, and has particular reference to apparatus useful in the practice ofsuch processes. The apparatus is characterized by simplicity of structure, versatility of application, and economy in manufacture and use.

A light-and-heat process of copying has been described in US. Pat. No. 3,094,4l7. A light-sensitive intermediate sheet is reflex exposed in close contact with the original. The exposed sheet is then heated in close contact with a sensitized receptor or copy sheet. A black-on-white copy of the original is thereby produced.

US. Pat. No. 3,234,868 describes one form of apparatus for carrying out the copying process just described. The apparatus includes a document-supporting pressure pad, a light box fitting over the pad, and a heating platen and cover which is stored within the light box for portability.

Another form of portable copying apparatus for light-andheat copying is described in U.S. Pat. No. 3,467,470. A folding light box for portability.

Another form of portable copying apparatus for light-andheat copying is described in US. Pat. No. 3,467,470. A folding light box is expandable to fit over a pressure 'pad. Heat is supplied by a floating heater shoe which presses the sheets against a rotating drive roller. The light box and heating station fit together within a carrying a case which holds the pressure pad and other supplies and equipment.

The present invention likewise provides light box, pressure pad, and heating station, and is of such light weight and small size as to be even more easily portable, while incorporating additional features and advantages.

In the drawing,

FIG. 1 is a schematic front elevation with portions cut away to show interior construction and partially in cross section,

FIG. 2 is a side elevation similar to FIG. 1, and

HO. 3 is a cross-sectional elevation of the heating station of FIG. 2 on an enlarged scale.

The copying apparatus consists of a cabinet 1] removably mounted on a base 12 and containing a light box 13 and a heating station 14. The base is removably heldto the cabinet by means of easily disconnected hinges 15 at the rear of the assembly and a clasp 16 at the front. The base consists of a rigid plastic support 17 formed with supporting feet 18 and covered with a soft compressible sponge layer 19, and with hinge and clasp components foldable to a position beneath the plane of the compressible surface.

The cabinet 11 is in the form of an open-faced box provided with a flat transparent rigid cover 20 across the open face. Within the cabinet is mounted the light box 13 comprising a reflector 21 having a rectangular flat perforated top 22 and sloping side and end walls 23 each having a narrow edge 24 directly adjacent and perpendicular to the transparent plate 20. Lamps 25 are supported in sockets 26 which are attached to the end walls of the cabinet 11 and centrally of the slanted end walls, as shown, the lamps extending well into the interior of the light box through holes in the slanted walls. An inner transversely arcuate reflective shield 27 is supported above the lamps and just beneath the perforate top 22. The configuration of the light box assembly is such as to provide essentially uniform illumination over the entire area of the transparent plate 20.

Also mounted within the cabinet 11 and above the forward slanted side 23 of the light box 13 is a heater station 14 comprising a flock-surfaced roller 28 supported on an axle 29 and rotatable by means of handcrank 30. The roller rotates within an open-faced heating shoe 3] containing a heating element 32, the flock coating providing sufficient resiliency to force a composite of copy paper and intermediate firmly against the heating surface whereby to obtain uniform conduction of heat therefrom. The same effect may be obtained with a velour sleeve on a surfaced supporting roller.

A stripper bar 33 is disposed along the exposed surface of the roller 28 and between the outer edges of the heating shoe 3!, thereby defining an upper'input channel 34 and a lower output channel 35. The lower portion of the stripper bar 33 extends into close proximitywith the surface of the roller 28 and has a curved lower surface 36 for a purpose to be described.

A timing mechanism 37-is also incorporated within the forward upper portion'of the cabinet ll to provide, through an indicator dial 38, means for determining the time of exposure. Where desired, a suitable constant speed motor may be inserted between the reflector and the cabinet wall at the end opposite the timer 37 to replace the handcrank 30, in which event the dial 38 may be connected directly to the drive shaft 29. An on-off switch 39 controls the lamps 25, whereas the heater 32, and the constant speed motor when such is used, remains continuously connected. It will be understood that cord and plug means, not shown, are provided for connecting to a source of electric power.

In using the copy machine, the cabinet 11 is tilted away from the base 12 around hinges 15 so that an original and a light-sensitive intermediate may be placed upon the base and in that order. The cabinet is lowered into position against the composite, the transparent plate 20 forcing the intermediate into close uniform pressure contact with the original against the compressible layer 19. The lamps 25 are then turned on by means of the switch 39 and for a time, as indicated at the dial 38, sufficient to complete the required reflex exposure. The lamps are then turned off, the cabinet tilted temporarily, and the intermediate removed and placed in face-to-face contact with a reactive copy sheet. This new composite is then inserted into the upper input channel 34 and is drawn uniformly past the heating shoe 31 and out the output channel 35 by rotation of the drum 28 imparted through the handle 30. The rate of rotation of the handlemay be judged by reference to the indicator 38 or by simply making a preliminary trial. It has been found that consistently good results may be obtained in this manner even by inexperienced operators.

The composite of intermediate and copy paper is removed from the roller 28 and directed outwardly through the channel 35 by means of the closely fitting lower portion of the stripper bar 33, the papers being forced against the curved lower surface 36. The pressing action applied by the roller 28 and shoe 31, and particularly at the elevated temperatures required in the copying process, imparts a pronounced curl to the papers which would normally be retained even after separation and cooling. Contact with the curved surface 36 while the sheets are still at the elevated temperature is found to be effective in eliminating this curling tendency as well as in initiating a separation of the two sheets, so that the copy, after removal of the intermediate, is found to lie flat and without any tendency to curl.

Surprisingly uniform illumination of the entire exposure area, up to at least the 8%Xl l inch size of ordinary office correspondence, is obtained with the apparatus described using conventional household incandescent filament bulbs. This result is in part provided by the curved reflector 27, and in part by the narrow edges 24 adjacent the transparent panel 20 and perpendicular thereto. These latter narrow edges in particular overcome the reduction in intensity of light which would otherwise be experienced along the marginal areas. The presence of the shield 27 additionally makes possible the presence of openings 40 in the top panel of the light box 13 to permit the dissipation of heat given off by the lamps 2S. Additional ventilation is supplied by an opening 41 in the rear wall, and openings 42 in the top, of the casing ll. With the structure described, up to as many as 10 copies in succession are easily made without difficulty from overheating of the exposure station whereas with a completely enclosed structure the temperature becomes excessive after as few as three or four A particular advantage of the structure described is that the entire weight of the apparatus is utilized in providing pressure contact between original and intermediate during the exposure step. Close contact between these elements during that stage of the copying process is essential if accurate reproduction is to be attained. The weight of the device, while substantially less than that of other devices offered for similar purposes, is still found to be entirely adequate when efficiently used in the manner described.

A further advantage of the apparatus is realized in its ability to make copies of portions of manuscripts, such for example as blue prints or tracings, which are of much larger areas than the exposure area of the device. For such purposes the base 12 is completely removed and slid beneath the manuscript to the desired location, and the intermediate is then put in place. The cabinet is placed over the assembly at the designated area for making the exposure, and a copy of that portion of the manuscript is then completed in the manner previously indicated. Again, the full weight of the apparatus is employed in obtaining full pressure contact between intermediate and original, the designated area is uniformly exposed, and a uniform highquality black-on-white copy is produced.

What is claimed is as follows:

I. A heating device for the heat processing of paperlike sheet materials, comprising an open-faced heating shoe, a roller disposed within the open face of said shoe and having a compressible surface, a stripper bar extending along said roller and across the open face of said shoe and defining therewith an input channel and an output channel, and means for uniformly rotating said roller, and wherein said stripper bar includes a stripping edge closely adjacent the surface of said roller for directing sheet material away therefrom and a surface extending from said edge in a direction to impart reverse curl to sheet material advanced thereagainst from said roller.

2. Apparatus adapted for the copying of graphic originals by I a light-and-heat process and comprising an exposure station and a heat development station in integral relationship, and wherein said heat development station comprises an openfaced heating shoe, a roller disposed within the open face of said shoe and having a compressible surface, a stripper bar extending along said roller and across the open face of said shoe and defining therewith an input channel and an output channel, and means for uniformly rotating said roller, and wherein said stripper bar includes a stripping edge closely adjacent the surface of said roller for directing sheet material away therefrom and a surface extending from said edge in a direction to impart reverse curl to sheet material advanced thereagainst from said roller.

3. Apparatus of claim 2 wherein said exposure station includes a reflector having a perforate top, sidewalls and end walls sloping outwardly from said top toward a transparent pressure-plate and terminating in narrow edges perpendicular to said plate and defining an exposure area, a transversely arcuate reflector adjacent said top and extending the full length and width thereof, and light sources disposed centrally inwardly of said end walls; and wherein said apparatus further includes a rigid support member having a soft compressible surface, removably hingedly attached to said apparatus and covering said transparent pressure-plate. 

1. A heating device for the heat processing of paperlike sheet materials, comprising an open-faced heating shoe, a roller disposed within the open face of said shoe and having a compressible surface, a stripper bar extending along said roller and across the open face of said shoe and defining therewith an input channel and an output channel, and means for uniformly rotating said roller, and wherein said stripper bar includes a stripping edge closely adjacent the surface of said roller for directing sheet material away therefrom and a surface extending from said edge in a direction to impart reverse curl to sheet material advanced thereagainst from said roller.
 2. Apparatus adapted for the copying of graphic originals by a light-and-heat process and Comprising an exposure station and a heat development station in integral relationship, and wherein said heat development station comprises an open-faced heating shoe, a roller disposed within the open face of said shoe and having a compressible surface, a stripper bar extending along said roller and across the open face of said shoe and defining therewith an input channel and an output channel, and means for uniformly rotating said roller, and wherein said stripper bar includes a stripping edge closely adjacent the surface of said roller for directing sheet material away therefrom and a surface extending from said edge in a direction to impart reverse curl to sheet material advanced thereagainst from said roller.
 3. Apparatus of claim 2 wherein said exposure station includes a reflector having a perforate top, sidewalls and end walls sloping outwardly from said top toward a transparent pressure-plate and terminating in narrow edges perpendicular to said plate and defining an exposure area, a transversely arcuate reflector adjacent said top and extending the full length and width thereof, and light sources disposed centrally inwardly of said end walls; and wherein said apparatus further includes a rigid support member having a soft compressible surface, removably hingedly attached to said apparatus and covering said transparent pressure-plate. 